Name: Black Locust (Robinia pseudoacacia)
Otherwise known as: Frisia, False Acacia
Habitat: A deciduous tree member of the Leguminosea family, growing up to 25m in well-drained woodlands in the world’s temperate areas. A native to North America, it has opposed, ovate leaf forms with clusters of pendulous, fragrant, white flowers that become the traditional leguminous bean pod. The bark and roots are poisonous.
What does it do: The bark, seed and roots contain the toxic albumins robin and fazin that can clot the red corpuscles in mammals, and which possess powerful emetic and purgative properties. Strangely, while lethal in large doses, leading to heart failure, the Native Americans used weak tinctures from the bark to combat cases of poisoning by Datura Stramonium.
The flowers contain glycosides and an essential oil of which is used to treat muscular spasms associated with disorders of the nervous system and to relax the abdominal muscles following childbirth. The flowers were made into fritters, jams and perfumes, and the seeds were processed into a pale red dye for textiles.
However, while popular as an ornamental in European cities, it is best known for its highly durable properties that have made it a favourite of the timber and farming industry. Black Locust is a rapidly growing tree and yields one of the hardest of woods, in fact it becomes more durable after cutting, and is harder, closer grained, and denser than oak. It was greatly valued by North American shipbuilders, providing the wooden nails (trenails) to secure planking and is still used for fence-posts, police batons, wheel axles and barrack room flooring. In Europe, the tree, which is very invasive, is grown to bind loose soils and form secure hedges. Care must be exercised when handling this plant as its spines will cause a festering wound that will take weeks to heal.
Alexander McCowan is author of The World’s Most Dangerous Plants